SU1024875A1 - Device for comparing voltages - Google Patents

Description

The invention relates to automation and computing devices with analog-to-digital converters and can be used to compare pulse amplitudes from coordinate photoreceivers. It is known devices for comparison of voltages, containing an amplifier, to the first and second inputs of which the sources of measured and reference voltages are connected, respectively, Schmitt trigger, to the first input of which the output of the amplifier is connected, as well as the first and second single-oscillators, whose inputs are connected respectively to the first and the second inputs of the Schmitt trigger, the second and third inputs of which are connected respectively to the outputs of the first and second single-shot 1. However, this device does not provide information about the comparison result if the measured voltage is less than the reference. It is also known device for; voltage comparison, containing comparators, the first and second inputs of which are connected to the corresponding sources of the compared voltages, and a logic unit consisting of D-triggers, D-inputs of which are connected to the outputs of the corresponding comparators, C-inputs are connected to the strobe bus, and The R inputs are to the reset bus 2. A disadvantage of the device is the need to form an external gating signal, the generation and synchronization of which with the input signal is difficult in some cases. In addition, before each voltage comparison cycle, to reset the triggers, it is necessary to generate a Reset signal, which also complicates the process of controlling the operation of this device. Closest to the invention by technical essence is a device for comparing voltages, containing two comparators, the direct and inverse inputs of which are cross-linked and connected respectively to the sources of the compared voltages h. A disadvantage of the known device is low noise immunity, since the comparators produce signals from pulses of opposite polarity that accompany the measured pulses, i.e. One of the i-Comparators generates a signal directly from the input pulses, and the second at the end of the emissions of these pulses. The aim of the invention is to improve the noise immunity of the device and enhance the functionality. The goal is achieved by the fact that a voltage comparison device containing the first and second xsaparators, the direct and inverse inputs of which are cross-linked and connected to the corresponding sources of the compared voltages, and the source of the strobe signal, are entered one-shot and first and second elements ZI-2ILI-NOT, the first and fourth inputs of which are combined and connected to the source of the strobe signal, the second input of the first element ZI-2ILI-NO and the fifth input of the second element ZI-2ILI-NOT combined and under Connected to the output of the first comparator, the fifth input of the first element ZI-2ILI-NOT kf the second input of the second: element ZI-2ILY-NOT combined and connected to the output of the second comparator, the output of the first element ZI-2ILI is NOT connected to the input of the first one of the vibrator, my output is connected to the sixth input of the first element ZI-2ILI-HE, and to the first output of the device, the output of the second element 3H-2H / W-HE is connected to the input of the second one-oscillator, the direct output of which is connected to the sixth input of the second element JH-2IL - NOT to the second output of the device, but inverse the outputs of the first and second single vibrators are connected respectively to the third, and their inputs of the second and first elements of the ZI-2, OR NOT. FIG. 1 is attached in principle (and the diagram of the proposed device for comparison of stresses; FIG. 2 diagrams explaining its operation. The device contains the first 1 and second 2 computers, the first 3 and the second 4 elements ZI-2, OR-NOT, the first 5 and the second 6 single-resistors, 7-0 resistors, sources P and 12 of the compared voltages, the gate source 13, the first T4 and the second 15 outputs of the device.The device can operate in two modes: in the non-gating mode; in the gating mode by an external signal. In non-gated mode, the device is operating as In the initial state, on the inverse outputs of the first 5 and second 6 single vibrators, the source 13 outputs a high level corresponding to a logical unit, the comparators 1 and 2 of the balancing inputs, using resistors 9 and 10, are shifted to obtain a low level on the outputs comparators, i.e., the comparators' output are logical zeros. The magnitude of the bias voltage of comparators 1 and 2 simultaneously determine their response thresholds (for example, K597SAZ, K521SAZ can be used as such comparators) plitud pulses received on the input buses to vhodykomparatorov exceeds a threshold comparator 1 or 2, the output of one of them is. signal. If comparator 1 is triggered, then at its output, during transients, pulsed signals appear that can take on many intermediate values. The sequence of such pulses through the first group of element 3 ZI-2ILI-NOT enters the one-way input of one-shot 5 (as such one-shot can be used one-shot with repeated start-up, for example K155AGZ), which starts only when a full-fledged logical difference occurs at its input. The time of formation of single vibrators 5 and 6 is equal to the larger of the durations of the compared stresses, and if the accompanying ones are chosen for longer, then the greater of the emissions. When a new vibrator 5 is started up, a low level appears on its 4 inverted output, blocking the first group of inputs of the element i | ZI-2ILI-NOT, and at the direct output - a high level that allows the passage of pulses through the second group of inputs of element 3 ZI-2ILI-NOT. After the completion of the compared pulses, accompanying spikes appear, comparing them to the output of the comparator 2 a pulse signal appears. Since the first group of inputs of the element ZI-2, OR-k is closed l s. (since it is blocked by a low level. From the inverse output of the one-shot 511, this pulse signal through the second group of inputs of the ZI-2ILI-NO 3 element enters the restarting of the one-shot 5. This results in the output of the device H by using the one-shot 5 with a restart, the authoritative level is generated for the duration of the compared pulses and their accompanying emissions, as well as the time of the one-shot 5 vibrator. Thus, the information obtained when the comparators are triggered background (noise / component signals, which prevents distortion of information about the result, the comparison of voltages. In the strobe mode by an external signal, the device operates as follows. At the output of the source of the strobe signal in the initial state is low (co zero). Logical the unit at the direct output of the corresponding one-shot 5 or 6 is generated whenever the signal at the output of one of the comparators 1 or 2 is accompanied by the appearance of a high level pulse (logical unit j on the output bus yes gating source. In this mode, during operation and at the end of the gating pulse, a low level from the inverse output of the corresponding single vibrator 5 or 6 (during its formation time) provides additional blocking of the passage of signals from comparators 1 or 2, when they are triggered by emissions or other interfering pulses. . The proposed device, in comparison with the known, allows to increase the noise immunity by eliminating false information obtained when the comparators are triggered from the background component of the signals; expands the functionality of the device, as it provides a comparison of voltages in the modes with gating and without gating; the number of control signals is reduced due to the fact that the device does not require the use of the Reset signal, and in the non-gated mode, it does not require an external pulse.

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Claims (1)

VOLTAGE COMPARISON DEVICE, containing the first and second comparators, the direct and inverse inputs of which are cross-connected and connected to the corresponding sources of the compared voltages, and the source, the gating signal, is different. the fact that, in order to increase the noise immunity of the device and expand the functionality, it introduced the first and second single vibrators and the first and second elements ZI-2ILI-NO, the first and fourth inputs of which are combined and connected to the source of the strobe signal, the second input of the first element ZI-2 OR NOT and the fifth input of the second element ZI-2 OR NOT connected and connected to the output of the first comparator, the fifth input of the first element ZI “2 OR NOT and the second input of the second element ZI-MLI NOT combined and connected to the output of the second comparator , the output of the first ZI-2ORI-NOT element is connected to the input of the first one-shot, the direct output of which _{p is} connected to the sixth input of the first JS of the ZI-2ORI-NOT element and to the first output of the device, the output of the second, ZI-2ORI-NOT element is connected to the input of the second one-shot the direct output of which is connected to the sixth input of the second element ZI-2OR-NOT and to the second output of the device, and the inverse outputs of the first and second single-vibrators are connected respectively with the third inputs of the second and first elements of ZI-2OR-NOT. „, .1024875